Hi I was wondering if this amount of fish would be ok for a 20 gallon long planted tank.

3 Oto's
7 neon tetras
7 cherry shrimp
7 female bettas

i might get the oto's tomorrow because I'm having trouble with algae in my tank. and most of my dwarf hairgrass and glossostigma plants are turning yellow-brown and has some string stuff covering it as well.I haven't gotten any fish yet and was wondering on how to proceed.

Ok, ya my tank has been running for over 5 weeks and I've got a lot of plants in my tank. So I'll add the otos first, get the neon tetras and quarantine the tetras and get some bettas. And when the tetras and bettas passed the quarantine period I should add them both at once in the tank? Or add the tetras first and then the bettas?